Hook-like fastening assembly



Jan. 20, 1970 G. c. BRUMLIK 3,490,107

HOOK -LIKE FASTENING ASS EMBLY Filed Oct. 16, 1967 I N VEN TOR.

GEORGE C BRUMLIK -6 (ls/Am? ATTORNEY United States Patent US. Cl. 24-2044 Claims ABSTRACT OF THE DISCLOSURE A self-gripping fastening assemblyconsisting of a plurality of fastening members secured in upstandingcondition from the surface of an article, wherein the fastening membersare formed of a length of wire filament prestressed into helical orspiral form and maintained in straightened condition by a coatingcapable of being shrink-treated. The coated, straightened wire is cutinto small pieces which are mounted in thick profusion on the articlesurface and the end portion of each coating is treated to cause it toshrink and recede, exposing an end section of wire which bends to itspre-stressed shape to provide the finished fastening member in the formof a rigid coated body terminating in a wire hook.

The present invention relates to fastening devices, and in particular toa novel and improved fastening means attachable to one surface andcapable of gripping an opposed surface in a self-adhering action. Inparticular, the invention relates to a novel type of fastening elementand to a new and improved method for making the same.

A self-gripping fastening assembly is presently marketed under thetrademark Velcro, and is employed for releasably fastening fabrics orother articles to each other. Such fastening assembly is commerciallyprovided in the form of pairs of fabric strips which are sewn orotherwise secured to the opposed surfaces of the fabrics or otherarticles to be attached to each other. On one of these strips, the outersurface is covered by rows of upstanding plastic loops of small size,while the outer surface of the other strip is covered by matching rowsof upstanding plastic loops. When the covered strip surfaces are pressedtogether, the hooks on one strip engage and grip the loops on theopposite strip so that the strip surfaces grip tightly together and theattached fabric or articles are releasably secured to each other.

While such conventional fastening assemblies provide convenient andefiective gripping action, they are subject to the disadvantage of beingrelatively expensive since the formation of the loops and hooks and themounting thereof on the fabric strips involves costly manufacturingoperations. In addition, there is a further disadvantage in that theassembly is such that a pair of strips must be employed for eachgripping application, and a strip must be individually sewn or otherwisesecured to each of the articles to be fastened together.

It is an object of the present invention to provide improved fasteningmeans attachable to the surface of any article and capable of grippinganother article of soft or penetrable composition, with which the firstarticle is brought into surface contact.

Another object of the invention is to provide selfgripping fasteningmeans of the character described, which is mounted on the surface ofonly one of the articles to be fastened together.

A further object of the invention is to provide a novel and improvedmethod of making and mounting fastening means of the type described,which method provides an inexpensive manufacturing operation and aproduct which may be made available at low cost.

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In accordance with the invention, there is provided a self-grippingfastening assembly comprising a plurality of fastening members securedto the surface of an article. Each of the fastening members includes asubstantially rigid, elongated body mounted on said article andprojecting perpendicularly from the surface thereof. Embedded in saidbody member is a thin filament which extends longitudinally through thecenter thereof and has an exposed portion which projects from theunmounted end of said body, this exposed filament portion being shapedin the form of a hook. The hook is shaperetaining and results from theprestressed helical or spiral form of the embedded thin filament.

This invention also contemplates a method for making the aforementionedfastening assembly which includes the steps of straightening apre-stressed coiled thin filament, coating the straightened filamentwith a shrinkable coating material of sufficient rigidity and thicknessto maintain the filament in straightened condition, cutting the coatedfilament into small pieces, mounting the small pieces in upstandingcondition from the surface of an article, and subjecting the endportions of the coating of the mounted pieces to shrink treatment tocause said end coating portion to recede and expose a bare filamentportion which bends into an exposed terminal hook.

Additional objects and advantages of the invention will become apparentduring the course of the following specification when taken inconnection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a length of wire filament of helicalform which is employed to form an element of the fastening assembly ofthe invention;

FIG. 2 is a plan view of a length of wire filament of spiral form whichmay be alternately employed to form an element of the fasteningassembly;

FIG. 3 is an enlarged sectional view of a portion of the wire filamentof FIG. 1 in straightened condition and covered by a coating inaccordance with the invention;

FIG. 4 is a sectional view showing a plurality of pieces of coated wiremounted on the surface of an article;

FIG. 5 is an elevational view showing the mounted pieces of FIG. 4 afterthey have been subjected to heat treatment to form the finishedfastening assembly of the invention; and

FIG. 6 is an elevational view, similar to FIG. 5, but showing analternate form of fastening assembly employing the spirally stressedwire filament of FIG. 2.

Referring in detail to the drawings, FIG. 1 shows a length of thin wire10 which is pre-formed into the threedimensional shape of a helix 12.The wire 10 is of very small diameter, being in the nature of afilament, and is made of flexible material such as springy metal, whichmay be stretched into straight linear form, but which will tend tospring back to its pre-formed helical shape. The filament may also bemade of glass or plastic.

The helically formed spring wire 10 is used as the basic constituent ofthe fastening elements of the present invention, and for this purpose,the length of wire 10 is stretched out into straight linear form and iscoated with plastic to maintain it in straight condition. FIG. 3 shows asmall section of the straightened wire 10 to which has been applied toan external coating 14 of rigid material.

The coating 14 may be made of any material capable of coating thestretched wire 10 and of hardening sufiiciently to maintain the wire inits straight linear condition. It must also be capable of shrinking whensubjected to heat or similar treatment. For example, the coating 14 maybe made of glass or of such plastics as cellulose acetate, cellulosebutyrate, nylon, polyacetal or polyvinyl chloride, which possess theaforementioned properties.

It will be observed in FIG. 3 that the coating 14 is applied in athickness which is substantially greater than the diameter of the springwire 10. Thus, the thickness of the outer coating is sufiicient tomaintain the inner springwire 10 in its straightened form and torestrain it from bending. The coating 14 may be applied to the wire byconventional co-extrusion process, by dipping, or in any other suitablemanner.

After the length of wire is stretched out and coated to form a straightlength of substantial extent, the coated wire is chopped or cut intosmall pieces 16 of substantially equal length. These are themselves ofnarrow diameter and in the nature of small filaments, and are mounted inupstanding position and in relatively thick profusion on the surface ofan article to be fastened. In FIG. 4 there is shown an article 18 whichmay be a piece of leather, for example, and which has an upper surface20. The coated pieces 16 may be blown under high air pressure onto thesurface of the article so that they become partially embedded in thesurface, as shown in FIG. 4. Alternately, the pieces may be applied tothe article surface by flocking methods, weaving processes, or otherembedding methods. In any event, the pieces are so mounted that theycover the selected area surface of the article in closely spaced randomformation, and so that each is upstanding from the article surface andsubstantially perpendicular thereto.

The article 18 may be a piece of leather, as described, or it may befabric or any other material capable of supporting the pieces 16 by theapplication method employed.

After the coated pieces 16 are mounted on the article 18, as describedabove, the outer free ends thereof are treated to cause the coatingmaterial to shrink and retract from the tip of the piece, exposing theinner spring wire 10 therein. For example, where the coating material ismade of glass or the heat-shrinkable plastics previously identified, thetips of the pieces may be subjected to a flame, causing the coatingmaterial to shrink or melt, but in any event to recede downwardly awayfrom the tip. This exposes a short end section of bare inner wire 10which, because of its pre-tensional condition, bends into the form of ahook 22. Because of the original helical form 12 of the wire 10, thebook 22 takes the threedimensional volute form shown in FIG. 5.

The finished fastening assembly 24 is thus illustrated in FIG. ascomprising a plurality of fastened members 26 mounted in closely spacedrelationship upon the surface 20 of the article 18 in an upstandingposition substantially normal to the surface 20. Each of the fasteningmembers 26 comprises a straight, filament-like body member 28 formed ofthe coating material 14 and inserted wire 10, and terminating at itsupper end in the exposed wire hook 22. The body members 28 aresubstantially stiff.

The surface 20 of the article 18 may now be pressed into engagement withthe surface of another article, which latter surface is soft orfrangible and thus capable of being penetrated by the wire hooks 22 tocause the two articles to adhere to each other. The other article may befabric, for example, or may be soft leather or provided with a nu-bbysurface, etc. When the articles are pressed together, the hooks 22 willgrip the opposed surface and the combined gripping action of themultitude of hooks will cause the articles to become tightly fastened toeach other, until they are forcibly pulled apart and separated.

It will be appreciated, that instead of applying a flame to the coatedpieces 16 for causing shrinkage of the coating, or otherwise heattreating the ends of the pieces, the

coating may be made of a plastic orother material which will shrink uponchemical treatment, in which case it is only necessary to dip the endsof the mounted pieces in the appropriate chemical until the desireddegree of shrinkage has been achieved. Similarly, certain coatings willshrink upon the application of corona discharge.

FIG. 6 shows an alternate form of fastening assembly 31) which isidentical to the assembly 24 shown in FIG. 5 and previously described,except that the bodies 32 of each of the fastening members 34 terminatein wire hooks 36 which are of different shape than the hooks 22. Thesewire hooks 36 are flat and two-dimensional, being generally in the formof a fish hook. This hook shape is achieved by employing in the processpreviously described a length of wire 40 pre-tensioned to take the formof the fiat spiral 42 shown in FIG. 2. The spiral wire is straightened,coated, cut, and applied to the surface 20 of an article 18 in the samemanner as previously described, but when the coating is treated toshrink, the exposed wire 4-0 will return to its spiral form, resultingin the hooks 36.

While the filament is shown and described herein by way of example, asbeing made of spring metal wire, as previously indicated, it may be madeof glass, plastic or similar non-metal material which is capable ofbeing prestressed in filament form to retain a spiral or helical shape.In any event, the filament is of such small diameter that the exposedhooks 22 or 36 formed thereby are in the nature of tiny sharp hookswhich can easily penetrate soft materials.

While preferred embodiments of the invention have been shown anddescribed herein, it is obvious that numerous additions, changes andomissions may be made in such embodiment without departing from thespirit and scope of the invention.

What is claimed is:

1. A self-gripping fastening assembly for releasably connecting togethera pair of articles, said fastening as sembly comprising a plurality offastening members secured to the surface of one of said articles, eachof said fastening members comprising a substantially rigid, linear,non-metallic elongated body mounted on said one article and projectingperpendicularly from said surface, a single thin filament embeddedwithin said body and extending longitudinally entirely through thecenter thereof, and having an exposed portion projecting from theunmounted end of said body, said exposed filament portion being shapedin the form of a sharp hook.

2. A self-gripping fastening assembly according to claim 1 in which saidthin filament is pre-stressed into coiled configuration.

3. A self-gripping fastening assembly according to claim 2 in which saidthin filament is pre-stressed into helical form and said hook is aportion of a helical turn.

4. A self-gripping fastening assembly according to claim 2 in which saidthin filament is pro-stressed into flat spiral form and said hook is aportion of a spiral turn.

References Cited UNITED STATES PATENTS 2,807,072 9/1957 Mersereau 161-66X 3,147,528 9/1964 Erb 24-204 3,277,547 10/ 1966 Billarant 24-204BERNARD A. GELAK, Primary Examiner

